Patients with Gaucher disease suffer from a lack of functional glucocerebrosidase enzyme (Gc). This study is designed to determine if cDNA encoding normal Gc can be introduced into macrophage precursors using a retroviral vector. CD34+ cells obtained from GCSF mobilized peripheral blood stem cells or from bone marrow will be transduced ex vivo. These transduced cells will be reinfused into the patient who will be monitored for toxicities as well as evidence of successful transfer and expression.